Field of the Invention
The present invention relates to the field of microbial fermentation, which relates to a novel method for improving microbial laccase production.
Description of the Related Art
Laccase (p-diphenoloxidase, EC 1.10.3.2) are a group of blue multicopper oxidases that are capable of oxidizing mono-, di- and polyphenols, aminophenols, methoxyphenols, aromatic amines and ascorbic acid. Various substrates can be oxidized by laccase catalysis, which extends the industrial application in pulp and paper industry, wastewater treatment industry, organic synthesis and so on.
Laccase is mostly produced from filamentous fungi, especially basidiomycetes and ascomycetes fungi. However, low laccase production from ascomycetes and basidiomycetes could hardly meet the growing demand for industrial utilization of laccase. Besides the bacteria, nutrients, and cultivation conditions, some kinds of stimulators affect the laccase production by basidiomycetes and ascomycetes. The copper ions are one of the compositions of laccase activity center and an effective stimulator for laccase synthesis as well. Meanwhile, some small-molecules aromatic compounds including guaiacol, veratryl alcohol, vanillin and cinnamic acid are also used as stimulators for improving laccase production because of the structure similarly to the lignin. However, the simulators are found to be usually very expensive, which lead to higher cost in laccase production. Meanwhile, production with addition of copper ions or aromatic compounds induces pollution to the environment, and results to following detoxification treatment for culture, which influences the industrialization of laccase application. A novel, economic, safe and efficient stimulator is necessary and will surely be an important researching direction for improving laccase production. It may also inject new energies into microbial fermentation and industrial production.